Greenhouse type multi-compressor heat pump drying device and segmented drying method

Abstract

The invention discloses a greenhouse type multi-compressor heat pump drying device which is composed of a heat pump cycle and a solar heating drying cycle. The heat pump cycle comprises at least two compressors, at least two condensers, two evaporators and two throttle valves, and the solar heating drying cycle comprises a greenhouse drying box, an adjusting air door, a draught fan and the like. Combined drying is achieved through the heat pump cycle and the solar heating drying cycle. The greenhouse drying box is made of sunlight transmissive materials such as glass, can fully absorb solar radiation heat to dry materials, forms a solar heating circulation path under driving of the draught fan and the adjusting action of the adjusting air door, and is used for increasing the air temperature for product drying. According to the greenhouse type multi-compressor heat pump drying device, temperature and humidity are adjusted by means of the adjusting air door, compressor frequency conversion and the like, air adjustment is more flexible, control is more accurate, the adjustment range is wider, and the drying process is sanitary, efficient and energy-saving.

Description

technical field [0001] The invention relates to a greenhouse type multi-compressor heat pump drying device and a segmented drying method, belonging to the technical field of heat pump drying. Background technique [0002] In the process of industrial and agricultural production, the drying of products is a high energy-consuming process. The heat pump drying equipment uses the reverse Carnot principle to absorb the heat of the surrounding environment and transfer it to the drying room to increase the temperature of the drying room. The built-in evaporator can condense and dehumidify the hot and humid air. The heat pump drying equipment can precisely adjust the temperature and humidity of the air to achieve the drying of materials. Solar energy is a clean and non-polluting renewable energy, which is rarely used in existing heat pump drying equipment. It is of great significance to save energy and reduce consumption by making full use of solar energy to dry products, but sola...

AI Technical Summary

Problems solved by technology

However, the existing heat pump drying equipment mostly uses fixed-frequency compressors, which adopt the start-stop adjustment method for the heat and humidity parameters of the dry air, which has the following two shortcomings: First, the compressor start-stop control is used, when the temperature is higher than the set value , stop the compressor, turn on the compressor when the temperature is lower than the compressor, the adjustment ability is limited, the temperature fluctuation of the controlled drying air will be large, and the adaptability to different materials and different drying processes is poor, which affects the drying speed of materials and also affects the drying process. Product quality; second, after the drying has reached a certain stage, the amount of moisture removed from the dry material will decrease, and the heat required will decrease. will cause the compressor to start and stop too frequently

However, when drying reaches a certain stage, especially in the later stage of drying, when a single variable frequency compressor is used, in order to meet the lower heat demand, the operating frequency of the compressor is too low, and the corresponding performance coefficient is also low, which will also affect the economy of heat pump drying. sex

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